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Tray-type supercritical CO2 fractionation column structure

6 factors reduce the cost of supercritical CO2 fractionation

Tray

The tray is the basic element of the gas-liquid two-phase contact of the tray tower. According to the structure, the tray can be divided into two types: the tray with an overflow device and the tray without an overflow device. Trays with overflow devices can be divided into bubbling trays and jet trays.

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Tray with an overflow device

Bubble tower

Bubble towers include valve towers, sieve plate towers, bubble cap towers, etc. Among them, valve towers are the most widely used plate towers, although their cost is slightly higher than that of sieve plate towers, and their production capacity and tower efficiency are also lower. It is slightly lower than the sieve plate, but its outstanding feature is its large operating flexibility.

6 factors reduce the cost of supercritical CO2 fractionation

The sieve plate tower has a simple structure, low cost, high production capacity, low-pressure drop, and high plate efficiency. In recent years, new types such as large-aperture sieve plates suitable for dirty liquids and guided sieve plates for large liquid-gas ratio occasions have appeared, making them more widely used. Its disadvantage is that it is easy to leak liquid and the operation flexibility is small.

Jet tray

Jet-type trays include rectangular trays, inclined-hole trays, etc., which open directional channels on the trays, and the normal of the channels forms an acute angle with the plane of the plate. When the airflow is ejected from the directional orifices, a large liquid The turbulent work of the gas interface and the fluid creates good mass transfer conditions.

No overflow device tray

Non-overflow trays (through-flow trays) include through-flow grid plates (with strip-shaped grid slits on the plates), through-flow sieve plates (with larger holes than overflow sieve plates) , Flow-through float valve towers, etc.

Advantage

Because the overflow device is omitted, the tray has the advantages of large production capacity, simple structure, small pressure drop, and not easy to be blocked, but the operating flexibility is small and the efficiency of the tray is low. Priority can be given to corrosive or dirty materials.

Notes

When the superficial velocity of the supercritical CO2 fractionation column is high, the phenomenon of liquid splashing at the top of the CO2 fractionation column is serious, and the process does not allow the entrainment of mist droplets in the gas exiting the tower, it is necessary to install a demister at the gas outlet end of the CO2 fractionation column top to reduce the entrainment of liquid droplets and ensure that the gas purity. Commonly used demisters include folded plate wire mesh type and swirl plate type.

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